This invention relates generally to a pull-type machine for harvesting crops from a field and, more particularly, to a lift linkage that defines header flotation limits and that can be secured for transport purposes.
Trailed harvesting implements, such as mower conditioners, with lift systems that are positioned with one or more hydraulic cylinders, require a mechanical device for positively locking the implement in the raised position to insure that during transport on the highway the implement will not lower due to a hydraulic leak or failure. It is desirable that a mechanism be provided to permit the operator to engage a lever before getting onto the tractor to start operation of the tractor and harvesting implement so that the locking device will automatically engage when the implement is raised into the transport position. It is also preferable that the mechanism bias the locking device in the locked position.
It would be further preferable that the same mechanism permit the operator, having arrived at the field, to engage the mechanism before getting into the tractor so that the locking mechanism will unlock when the implement is raised fully, thereby allowing the operator to commence use of the implement without again dis-mounting from the tractor to unlock the locking device. It would also be desirable that the mechanism also hold the locking device in the unlocked position such that the locking device will not engage when the implement is raised during field operation to clear the cut crop or an obstacle.
Crop harvesting headers are suspended from the harvester frame for flotational movement relative thereto. It is desirable to provide a device to define the range of operation for the flotational movement of the header. It is further desirable that the flotation limit be convertible to secure the header when in the transport position to prevent the header from bouncing during transportation thereof over the ground and, thereby, contacting other structural components of the harvester and effecting damage thereof.